The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
Distribution gearboxes, commonly referred to as transfer gearboxes, are gearboxes that are operable for splitting a drive torque produced by the drive unit of a motor vehicle to a plurality of outputs. Transfer gearboxes of this type are typically used in motor vehicles having a drivetrain configured to provide either permanent or switchable four-wheel or all-wheel drive modes of operation. Such transfer gearboxes are typically operable to distribute the drive torque produced by the drive unit to two driven axles of the vehicle, the distribution being predefined or capable of being freely selected depending on the particular design of the transfer gearbox. In order for it to be possible to control the transmission and distribution of drive torque to the two axles of the motor vehicle, a clutch unit is provided which, for example, affords the option to the driver of the motor vehicle to select between a first or permanent two-wheel drive mode, in which the drive of the vehicle takes place exclusively via a primary axle, and a second or automatic four-wheel drive mode, which is also known as an “on-demand drive mode”. In this second mode, a certain proportion of the drive torque is transmitted to the wheels of the other axle (a secondary axle) depending on the driving conditions, in order to provide temporary four-wheel drive.
EP 1 582 777 A2 discloses a distribution gearbox equipped with a chain sprocket. The chain sprocket is mounted by means of a dedicated bearing with respect to the housing.
The centre differential for a vehicle with four-wheel drive in accordance with DE 38 05 284 A1 has an input shaft, a clutch and a chain sprocket, the latter being mounted on both sides in a manner which is fixed to the housing. DE 37 05 064 A1 also discloses a mounting of this type.
The distribution gearbox of US 2008/308354 A1 discloses a mounting of the chain sprocket on the input shaft by means of radial needle bearings.
DE 10 2007 057 984 A1 describes a distribution gearbox with a chain drive and a clutch. Lubricant is delivered by a delivery device from an oil sump which lies below the chain drive into regions which are situated above.